The latest developments of internet streaming protocols for delivering multimedia content brought up protocols that allow transmitting content as a set of time-bounded content elements, also referred to as chunks, that are physically separated (e.g. a file is created for each chunk of content) or logically separated (e.g. all chunks of content are stored in a single file with an addressing structure that allows to access any chunk individually). The former technique is used by HTTP Live Streaming or 3GPP adaptive HTTP Streaming, whereas the latter technique is employed by Microsoft Smooth Streaming.
Premium content, such as pay television in e.g. video-on-demand applications, continues to require protection in order to prevent unauthorized access to such content and to detect leaks in the protection. Whereas unauthorized access to content may e.g. be avoided by using encryption techniques, tracing of content is usually performed by employing watermarks. Watermarking involves the insertion of (unique) information into the content in a non-removable manner and in a manner typically not or hardly noticeable for the user at the receiving side. Watermarking allows the identification of a source that redistributes premium content without authorization.
Multiple parties are usually involved in the distribution of content to end users, such as a content creator, a content aggregator, one or more network providers etc. If each participant in the distribution chain inserts their own watermark without consideration of watermark embedding efforts of other parties, there is a potential for overlapping or colliding watermarks which results e.g. in content encoding inefficiencies.
There is a need in the art for efficient watermarking of content in a multiparty content providing environment.